16 Practical guidance
These practicals are included to give ideas for activities to support OCR A-level Biology
Units F215 [5.4.3: Animal behaviour] and F216: Practical skills in Biology 2.
The practicals chosen relate closely to the learning outcomes, and may be used to develop
students’ practical skills in preparation for practical assessment.
However, they are not intended to form a complete practical course.
Safety
Although great care has been taken in checking the accuracy of the information provided, Cambridge
University Press shall not be responsible for any errors, omissions or inaccuracies.
Teachers and technicians should always follow their school and departmental safety policies. You
must ensure that you consult your employer’s model risk assessments and modify them as appropriate
to meet local circumstances before starting any practical work. Risk assessments will depend on your
own skills and experience, and the facilities available to you. Everyone is responsible for his or her
own safety and for the safety of others.
The practicals should be carried out by teachers themselves before they are presented to students.
Additional notes relating to each activity in this chapter are given below. These include, where
appropriate, references to Hazcards and the CLEAPSS Laboratory Handbook, both of which provide
model risk assessments and are available to CLEAPSS members.
The notes given below also contain some background information and advice, but in no way should
they be regarded as risk assessments. Teachers and technicians are advised to read the relevant
sections of the CLEAPSS Laboratory Handbook for further advice and guidance. The Handbook
includes a great deal of useful background information and is an excellent source of references.
Practical 1: Investigating the response of Tribolium to humidity
Hazcards: 19A
There are various types of choice chamber. The sort used here can be purchased in packs of five from
Griffin Education (Ref. YTD-190-M). Tribolium beetles and Tribolium culture medium can be
purchased from Blades Biological Ltd (www.blades-bio.co.uk).
Other small invertebrates, such as woodlice or maggots (blowfly larvae), can be used in the choice
chamber.
The behaviour shown by the beetles is a kinesis, where the speed of movement or frequency of turning
depends on the strength of a stimulus; in this case, the degree of humidity.
Choice chambers can be used to investigate responses to other factors, such as light and dark.
The use of the chamber with no water or calcium chloride is a control to check that there is no factor
in the room affecting the distribution of the beetles. Students can carry out a 2 test on the numbers.
This should show that there is no significant association of numbers with left or right. This will allow
them to expect 50 : 50 proportions in the second part of the experiment, where they can carry out
another 2 test for association between humid/dry conditions and numbers of beetles.
This investigation is adapted from Revised Nuffield Advanced Science (Biology) (Longman 1985),
Practical Guide 4: Coordination, Response and Behaviour, pp. 27–29.
COAS Biology 2 Teacher Resources
Original material © Cambridge University Press 2009
1
16 Practical guidance
Practical 2: Investigating mirror learning in humans
Some experimentation is needed with the angles of cardboard sheet and mirror, so that the subject can
see the reflection of the star in the mirror without seeing the star itself. It may be easier to use two
stands to hold the sheet.
Suitably sized mirror tiles make good alternatives to glass mirrors.
The double star should be about 10 cm across, and the double lines about 8 mm apart. Draw a master
copy and photocopy it.
At first, the subject will find mirror drawing very difficult, as the brain sends the hand the wrong
information. The first trial will take a very long time, with numerous errors. However, the subject will
soon learn to adapt to the new situation, and the graphs should show a rapid decrease in trial time and
number of errors.
There is a great deal of variation in the ability of individuals to learn the new skill. Some learn
quickly, others don’t improve much over 15 trials. (Teachers should try the experiment – it’s not
easy!)
The newly learned skill could be tested to see if it transfers to other shapes such as squares, mazes etc.
This investigation is adapted from Revised Nuffield Advanced Science (Biology) (Longman 1985),
Practical Guide 4: Coordination, Response and Behaviour, pp. 50–51.
COAS Biology 2 Teacher Resources
Original material © Cambridge University Press 2009
2